New research from a University of Rochester group finds that stresses like poverty or depression can lead to a variety of different parenting problems, such as neglect, hostility, and insensitivity.

Melissa Sturge-Apple, assistant professor of psychology at the University of Rochester and lead author on the Development and Psychopathology paper to be published October 19, said that stress “literally changes the way a mother’s body responds to the normal demands of small children and those changes make it much harder to parent positively.”

“Stress is not just in our heads, it’s in our bodies,” she added.

The study is the first to measure physiological stress response in real time. Participants reactions were measured using an ECG monitor that was specifically developed for the study by University of Rochester engineers. This device allowed the researchers to analyze subtle changes in mothers’ heartbeats, which was an indicator as to how they were handling different situations.

In the study, 153 mothers and their 17-to-19-month old children were monitored in two-hour intervals. Mothers with hyperactive stress responses had the highest levels of hostility with their toddlers, including rough physical interaction and derogatory comments.

Sturge-Apple points out that the study confirms what clinicians have long observed: that depression in mothers sometimes is linked to harsh, highly reactive parenting, not subdued mothering. In contrast, mothers who were struggling with poverty exhibited underactive stress response systems. Their heart rate patterns were lowered and stayed lower even if children exhibited distress.